Most telephone systems are capable of preventing telephone connections from being established according to the telephone number dialed. Such systems are provided by a telephone service provider and typically are used to block telephone calls that would incur a fee, such as long distances calls or numbers having a "1-900" or "1-976" prefix. See for example, U.S. Pat. Nos. 3,786,196 and 5,109,408.
Recently, federal, state and industry-imposed telephone solicitation laws and regulations mandate that a consumer, who expresses a desire not to be solicited by telephone, not be called. By regulation, a list must be maintained by each company and is commonly called a "do-not-call" list. In order to comply with these laws and regulations, most companies have instituted a procedure whereby a telephone solicitor prepares a memo listing the telephone numbers for which consumers have indicated a desire not be solicited. These numbers eventually are provided to the telephone service provider of the company. The telephone service provider programs the central office (e.g. 40 in FIG. 3) associated with the company's office to prevent telephone calls to the listed telephone numbers from phones within the company. Other individual offices in the company are not prevented from calling numbers on the "do-not-call" list unless the telephone service provider programs each individual number in each central office associated with each office of the company.
One problem with this methodology is that the ability to add a number to a set of prohibited numbers requires a significant amount of manual effort, which is fraught with error, delay, and requires the telephone service provider to do the programming. It also is difficult to override the blocking system without repeating the entire process in reverse. For example, a personal or other acceptable business call to a number would be completely blocked because the number is on the "do-not-call" list.